Crocodile makes short work of bull shark | VIDEO

Brutus, a monster crocodile, with a bull shark between its jaws on the Adelaide River in the Kakadu National Park. Photo: Andrew Paice

Which animal would win in a fight between a croc and a shark?

It sounds like a hypothetical question, perhaps posed between a few mates at the pub, but a boatload of tourists had a front-row seat to the battle in the Northern Territory this week.

Sydney man Andrew Paice was on a tour with his family on the Adelaide River in the Kakadu National Park on Tuesday when he saw Brutus, a monster crocodile who has become somewhat of a tourist attraction in the far north, with something clenched between his huge jaws.

The tour guide swung the boat around to reveal that Brutus, who is estimated to be 80 years old and 5.5 metres long, crunching down on a bull shark.

"It was pretty astonishing, because I suppose we didn't really think about sharks," Mr Paice, from Forestville in Sydney, said.

"We were obviously trying to spot crocodiles, we didn't think sharks would be in that water too.

"The shark was still alive, it was still wriggling around quite a lot and thrashing around. It was amazing to see, and to see it so clearly as well."

Mr Paice said the shark was between one and 1.5 metres long. He said the tour had been coming to an end when he and about 25 other tourists on the boat saw a commotion in the water.

"We were on our way back to the jetty. We'd already seen Brutus once, and when we were going back in, he had something in his mouth and we thought it was a fairly big fish," Mr Paice said.

"Morgan [the tour guide] brought the boat a bit closer and we realised it was a shark.

"We watched it for probably a good five or 10 minutes. The crocodile slid back into the water with the shark, and then the crocodile started to take it back into the mangroves to have it for himself.

"The shark was still thrashing around a little bit. Because Brutus is such an old croc, his teeth aren't really good, so he couldn't quite puncture him well enough."

Mr Paice said his seven-year-old daughter, Madison, had become accustomed to crocodiles jumping beside the boat by the end of the tour, but she still had a few questions about Brutus' meal.

"She was asking a lot of questions, like 'Where did the shark come from? How come it got a shark? How did it catch it?' We were even asking how it caught it. She was quite amazed by it as well," Mr Paice said.

Mr Paice is four months into a year-long adventure around Australia with his partner Nikki and their daughter, and said he was a keen photographer.

"I'm a try-hard amateur photographer. Ask my partner; all she sees is me glued to the eyepiece. We've been on the road for about four months, and I've taken 6500 photos or so," he said.

But Brutus' snap-shot would have to be a highlight so far.

A Taronga Zoo spokesman said a shark would usually be able to evade a crocodile in deeper water, but at shallower depths it was "entirely feasible" for a crocodile to overpower a shark.

"This fellow [Mr Paice] has been incredibly lucky, because in general you don't see a lot of animals successfully hunting. It is quite a unique thing that he has witnessed," the spokesman said.

"Crocs are quite opportunistic, they will eat anything they can overpower. When you're dealing with a five-metre crocodile, they're tremendously capable. Here you've got a meeting of two Top End predators, and in this instance the croc has managed to grab the shark and is using its remarkable strength to overpower it."